@thomasfuchs just some information I found since I had heard of stuff like this before. This article by one Robert Bateman, details what invalidates the legality of T&C (and also clarifies that T&C and TOS are interchangeable).

"Yes, Terms and Conditions are legally binding. Or at least, they can be legally binding if:

You have obtained acceptance in the proper way. This means that your customer has actively agreed to your Terms and Conditions."

The article goes on to explain other invalidations, but by not responding to an email, you are not actively agreeing to the terms. However if you were to log on to the site and click "I accept" that is likely a different case

Edit to add: I still think people should comply because corporate lawyers gonna do their jobs, but im just stating for everyone's sake, as far as I can tell, this is not legal